ES2899035T3 - Polyurethane foam article and method of forming the same - Google Patents

Abstract

A polyurethane foam article comprising the reaction product of: (A) an isocyanate component comprising an isocyanate prepolymer, said isocyanate prepolymer comprising the reaction product of: (i) a first polyether polyol; and (ii) a diphenylmethane diisocyanate, said diphenylmethane diisocyanate comprising: from 40% by weight to 60% by weight of 2,4'-isomer based on the total weight of diphenylmethane diisocyanate; from 40% by weight to 60% by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and less than 10% by weight of 2,2'-isomer based on the total weight of diphenylmethane diisocyanate; and (B) an isocyanate-reactive composition comprising: (i) a second polyether polyol having terminal secondary hydroxyl groups; and (ii) an amine-initiated catalytic polyol polyether having primary hydroxyl groups; in the presence of a foaming agent.

Description

DESCRIPTION

Polyurethane foam article and method of forming the same

Background of the invention

1. Field of the Invention

The subject matter of the invention relates generally to a polyurethane foam article and a method of forming the polyurethane foam article. More specifically, the subject matter of the invention relates to a method of forming a polyurethane foam article comprising the reaction product of an isocyanate-reactive composition and an isocyanate component, in the presence of a foaming agent.

2. Description of Related Art

The use of polyurethane foam articles in the transportation, construction, sports and other industries is known in the art. In the sports industry, polyurethane foam articles are used to make surfboards. Like surfboards, polyurethane foam items provide excellent buoyancy combined with excellent strength and durability.

As is known in the art, polyurethane foam articles are formed by the exothermic reaction of an isocyanate-reactive resin composition and an isocyanate in the presence of a foaming agent. The isocyanate-reactive resin composition, the isocyanate, and the foaming agent, collectively known as the polyurethane system, are selected to optimize the manufacturing efficiency and performance properties of the polyurethane foam article for a particular use. For example, when polyurethane foam is used for a surfboard, the components of the polyurethane system are selected for molding efficiency and to produce a polyurethane foam article (for example, a surfboard core) that have exceptional buoyancy, strength, durability, color, color stability, and other performance properties. In surfboard applications, the isocyanate-reactive resin composition and the isocyanate are typically mixed in the presence of the foaming agent to form a reaction mix, which is injected into a mold and reacts to form a surfboard core. . In past surfboard applications, toluene diisocyanate has been used to form buoyant surfboard cores having excellent strength and color (ie, white color). However, safety and environmental concerns have started to prevent surfboard manufacturers from using toluene diisocyanate.

Recently, surfboard manufacturers have attempted to use monomeric and polymeric diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and other isocyanates for the production of surfboard cores. Many of these attempts have failed. For example, the use of monomeric and polymeric diphenylmethane diisocyanate often causes surfboard cores to discolor, split, scorch, burn, stick to the mold and other problems associated with an uncontrolled exotherm which is generated during the formation of surfboard cores. Furthermore, once formed, surfboard cores formed with monomeric and polymeric diphenylmethane diisocyanate may exhibit poor strength and color stability.

To this end, various polyurethane systems which do not use toluene diisocyanate have been developed in an attempt to produce surfboard cores. US 6423755 refers to rigid polyurethane foams which have a unique combination of moderately low density, useful in the automotive industry. Document WO 2008/014227 on the other hand refers to polyurethane and polyisocyanurate foams for use in surfboards and pre-boards. Also, document EP 0118725 refers to mixtures of polyisocyanates of diphenylmethane diisocyanates which are liquid at room temperature and can be processed to give groups of polyurethane, polyisocyanurate and/or polyurea plastics resistant to abrasion, fire retardant and, in particular, low cell shrinkage or compact. Despite such development, there is a need to further improve polyurethane systems and surfboard cores formed from them.

Summary of the invention and advantages

The subject matter of the invention provides a polyurethane foam article comprising the reaction product of an isocyanate component and an isocyanate-reactive composition in the presence of a foaming agent. The isocyanate component includes an isocyanate prepolymer comprising the reaction product of a first polyether polyol and a diphenylmethane diisocyanate, said diphenylmethane diisocyanate comprising: from 40% by weight to 60% by weight of 2,4'- isomer based on total weight of diphenylmethane diisocyanate; from 40% by weight to 60% by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and from 40% by weight to 60% by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and less than 10% by weight of 2,2'-isomer based on the total weight of diphenylmethane diisocyanate. The composition reactive with isocyanate it comprises a second polyether polyol having terminal secondary hydroxyl groups and an amine initiated catalytic polyether polyol having primary hydroxyl groups.

The subject matter of the invention also provides a method of making the polyurethane foam article comprising the steps of reacting the first polyether polyol and diphenylmethane diisocyanate to form the isocyanate prepolymer and reacting the isocyanate prepolymer with the reactive composition with isocyanate in the presence of the foaming agent to form the polyurethane foam article.

Advantageously, the polyurethane foam article can be safely and efficiently manufactured to produce a polyurethane foam article (eg, a surfboard core) having buoyancy, strength, durability, color, color stability, and other properties. exceptional performance.

Detailed description of the invention

A polyurethane foam article is disclosed. The polyurethane foam article results from an exothermic reaction of a polyurethane system comprising an isocyanate-reactive resin composition and an isocyanate component in the presence of a foaming agent. The polyurethane foam article of the present invention is typically used as a surfboard core. However, it should be appreciated that the rigid polyurethane foam of the subject matter can also be used for many other applications. The subject matter of the invention provides a polyurethane foam article comprising the reaction product of an isocyanate component and an isocyanate-reactive composition in the presence of a foaming agent. The isocyanate component includes an isocyanate prepolymer comprising the reaction product of a first polyether polyol and a diphenylmethane diisocyanate, said diphenylmethane diisocyanate comprising: from 40% by weight to 60% by weight of 2,4'- isomer based on total weight of diphenylmethane diisocyanate; from 40% by weight to 60% by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and from 40% by weight to 60% by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and less than 10% by weight of 2,2'-isomer based on the total weight of diphenylmethane diisocyanate. The isocyanate-reactive composition comprises a second polyether polyol having terminal secondary hydroxyl groups and an amine-initiated catalytic polyether polyol having primary hydroxyl groups. The unreacted isocyanate-reactive resin composition, isocyanate component, and foaming agent are collectively referred to as a polyurethane system.

The polyurethane foam article includes the reaction product of the isocyanate component and the isocyanate-reactive composition in the presence of the foaming agent, ie, the isocyanate prepolymer and the polyols of the isocyanate-reactive component react chemically in the presence of the foaming agent. The present description also describes a polyurethane system comprising the isocyanate component and the isocyanate-reactive component. The system is typically provided in two or more discrete components, such as the isocyanate component and the isocyanate-reactive composition (or resin), i.e., as a two-component (or 2K) system, which is described below. It should be appreciated that reference to isocyanate component and isocyanate-reactive composition, as used herein, is simply for purposes of establishing a reference point for the placement of the individual components of the system, and to establish a parts base. in weigh. As such, it should not be construed as limiting the present description to just a 2K system. For example, the individual components of the system can be kept separate from one another and individually mixed prior to application. As another example, a component typically included (and described herein as such) in the isocyanate-reactive composition may be mixed and used with the isocyanate component.

The polyurethane foam article of the present disclosure typically has a closed cell content of greater than about 85, alternatively from about 85 to about 95% when tested in accordance with ASTM D2856-94.

The polyurethane foam article of the present disclosure typically has a density of from about 16 to about 240, from about 24 to about 80, from about 28 to about 60, from about 40 to about 60, from about 47 to about 52 kg/ m3 when tested in accordance with ASTM D1622-14.

The polyurethane foam article of the present invention can be described as a "rigid polyurethane foam." The term "rigid polyurethane foam" describes a particular class of polyurethane foam in contrast to flexible polyurethane foam. Rigid polyurethane foam is generally non-porous, has closed cells and minimal elastic characteristics, while flexible polyurethane foam is generally porous and has open cells.

The Isocyanate Component

The polyurethane system of the present disclosure includes the isocyanate component. The isocyanate component includes the isocyanate prepolymer. The isocyanate prepolymer comprises the reaction product of the first polyether polyol and diphenylmethane diisocyanate. In some embodiments, the isocyanate prepolymer consists essentially of the reaction product of the first polyether polyol and the diphenylmethane diisocyanate in the presence of various additives. In some embodiments, the isocyanate prepolymer consists of the reaction product of the first polyether polyol and diphenylmethane diisocyanate.

Polyether polyols as described herein and suitable for the purposes of the present invention include, but are not limited to, products obtained by polymerization of a cyclic oxide (i.e., an alkylene oxide), e.g. of ethylene (EO), propylene oxide (PO), butylene oxide (BO) or tetrahydrofuran in the presence of polyfunctional initiators. Suitable starter compounds contain a plurality of active hydrogen atoms, and include water, butanediol, ethylene glycol, propylene glycol (PG), diethylene glycol, triethylene glycol, dipropylene glycol, ethanolamine, diethanolamine, triethanolamine, toluenediamine, diethyltoluenediamine, phenyl diamine, diphenylmethanediamine, ethylenediamine, cyclohexane diamine, cyclohexane dimethanol, resorcinol, bisphenol A, glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, and combinations thereof.

To this end, the polyether polyols as described herein include a plurality of alkyleneoxy groups. The term "alkyleneoxy group" describes a mer, or a unit. The alkyleneoxy group is the unit which results from the polymerization of alkylene oxide, for example, EO groups, PO groups and BO groups. If referenced, the amount of alkyleneoxy groups in the polyether polyols is referenced in parts by weight, based on the total weight of the alkyleneoxy groups used to form the polyether polyol. The plurality of alkyleneoxy groups can be arranged to form polyether polyols which are described as polyols having random alkyleneoxy groups (forming hetero segments), polymers having repeating alkyleneoxy groups, and polymers having block alkyleneoxy groups. The plurality of polymeric side chains have alkoxy end caps selected from the group of ethyleneoxy end caps, propyleneoxy end caps, butyleneoxy end caps, and combinations thereof. The amount of alkyleneoxy end caps in polyether polyols is referred to in percent (%), based on the total number of end caps in a sample of the particular polyether polyol.

Referring now to the first polyol polyether, the first polyol polyether typically has a functionality of greater than about 2, alternatively greater than about 3, alternatively from about 2 to about 5, alternatively from about 3 to about 5, alternatively about 4; a weight average molecular weight of from about 200 to about 900, alternatively from about 300 to about 700, alternatively from about 300 to about 500, alternatively from about 350 to about 450 g/mol; a hydroxyl number of from about 30 to about 1100, alternatively from about 400 to about 900, alternatively from about 435 to about 570, alternatively from about 435 to about 465, alternatively from about 540 to about 570 mg KOH/g; and a viscosity at 20°C of from about 1,000 to about 8,000, alternatively from about 4,000 to about 6,000, alternatively from about 4,800 to about 5,600 cps when tested in accordance with ASTM D2196-15. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

In some embodiments, the first polyether polyol is started with pentaerythritol. An initiator, also called a promoter, functions as a reaction base for compounds, such as alkylene oxides, which polymerize to form polyols, and also serves to anchor polyols during formation. The first polyether polyol of these embodiments may comprise EO, PO and/or BO groups and has various percentages of PO coverage. The first polyether polyol has greater than about 90, alternatively greater than about 95, alternatively greater than about 99, alternatively about 100% PO coverage. More specifically, by "approximately" 100% coverage with PO, it is meant that all of the intended coverage of the first polyether polyol is a terminal coverage with PO, with no EO coverage resulting from traces of other alkylene oxides or other impurities. As such, the coverage is typically about 100% PO coverage, but can be slightly lower, such as at least about 99% PO coverage, and depends on process variables and the presence of impurities during processing. production of the first polyether polyol.

In one embodiment, the first polyether polyol is a pentaerythritol-initiated polyether polyol with a PO end cap which has: a functionality of about 4; a weight average molecular weight of about 400 g/mol and a hydroxyl number of about 555 mg KOH/g.

Referring now to diphenylmethane diisocyanate, diphenylmethane diisocyanate is a liquid having an NCO content (wt%) of about 33.5. Determination of NCO content (% NCO) is performed by standard chemical titration analysis known to those skilled in the art. Diphenylmethane diisocyanate includes isomers selected from the group of 2,2'-isomer, 2,4'-isomer and 4,4'-isomer.

In one embodiment, the diphenylmethane diisocyanate comprises: less than 10 % by weight of the 2,2'-isomer; from about 40 to about 60% by weight of the 2,4'-isomer; and from about 40 to about 60% by weight of the 4,4'-isomer, with the % by weight based on the total weight of diphenylmethane diisocyanate. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

In another embodiment, the diphenylmethane diisocyanate comprises: trace amounts (eg, less than 1, less than 0.5% by weight) of the 2,2'-isomer; about 50 wt% (eg, 50 ± 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, wt%) of the 2,4'-isomer; and about 50 wt% (eg, 50 ± 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, wt%) of the 4,4'-isomer.

In yet another embodiment, the diphenylmethane diisocyanate includes about 50% by weight of the 2,4'-isomer based on the total weight of the diphenylmethane diisocyanate and the other about 50% comprises any combination of the 2,2'-isomer and 4, 4'-isomer.

As stated above, the isocyanate prepolymer comprises the reaction product of the first polyether polyol and diphenylmethane diisocyanate. In various embodiments, the first polyether polyol is present in the isocyanate prepolymer in an amount of from about 2 to about 20, alternatively from about 5 to about 15, alternatively from about 7 to about 10% by weight based on the total weight of said isocyanate prepolymer and said diphenylmethane diisocyanate are present in said isocyanate prepolymer in an amount of from about 80 to about 98, alternatively from about 85 to about 95, alternatively from about 90 to about 93% by weight based on the total weight of said isocyanate prepolymer. Of course, the isocyanate prepolymer comprises the reaction product of the first polyol polyether and diphenylmethane diisocyanate, and the above ranges are essentially, or may alternatively be considered, the amounts of the first polyol polyether and reacted diphenylmethane diisocyanate and to form the isocyanate prepolymer. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

In addition, embodiments are contemplated herein, wherein the isocyanate prepolymer comprises the reaction product of more than one isocyanate (eg, different isocyanates in addition to diphenylmethane diisocyanate) and/or more than one polyol (eg, different polyols in addition to the first polyether polyol). In such embodiments, the total amount of all included polyols is within the above ranges.

The chemical reaction of the first polyether polyol and the diphenylmethane diisocyanate to form the isocyanate prepolymer may be carried out in the presence of one or more additives. Suitable additives for the purposes of the present invention include, but are not limited to, catalysts, chain extenders, crosslinkers, chain terminators, reaction inhibitors, processing additives, plasticizers, adhesion promoters, antioxidants, defoamers, antifoaming agents. , water scavengers, molecular sieves, fumed silicas, ultraviolet light stabilizers, fillers, thixotropic agents, silicones, colorants, inert diluents, and combinations thereof. In some embodiments, the reaction occurs in the presence of a reaction inhibitor such as benzoyl chloride and/or a plasticizer such as tributylphosphite. If included, the additive may be included in the isocyanate-reactive resin composition in various amounts. For example, in amounts less than 5, 4, 3, 2, 1, 0.5, 0.1, 0.5, 0.005 to 0.03% by weight based on the total weight of the reactants used to form the prepolymer or based on the total weight of the prepolymer.

In many embodiments, the isocyanate prepolymer has a specific gravity of about 1.05 to 1.10 g/cm3 and is a liquid at 25°C. Furthermore, in many such embodiments, the isocyanate prepolymer has a viscosity of from about 900 to about 1300, alternatively from about 900 to about 1300 cps at 25°C. Furthermore, in many such embodiments, the isocyanate prepolymer has an NCO content of from about 15 to about 40, alternatively from about 20 to about 30, alternatively from about 26 to about 28% by weight. Determination of NCO content (% NCO) is performed by standard chemical titration analysis known to those skilled in the art. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description. In some embodiments, the isocyanate component includes one or more types of supplemental isocyanates. The supplemental isocyanate may be a polyisocyanate having two or more functional groups, for example two or more NCO functional groups. Suitable supplemental isocyanates for the purposes of the present disclosure include, but are not limited to, aliphatic and aromatic isocyanates. In various embodiments, the supplemental isocyanate is selected from the group of diphenylmethane diisocyanates (MDI), polymeric diphenylmethane diisocyanates (pMDI), toluene diisocyanates (TDI), hexamethylene diisocyanates (HDI), isophorone diisocyanates (IPDI), and combinations thereof.

The supplemental isocyanate may be a supplemental isocyanate prepolymer which is different from the isocyanate prepolymer mentioned above. The supplemental isocyanate prepolymer is typically a reaction product of an isocyanate and a polyol and/or a polyamine. The isocyanate used in the supplemental isocyanate prepolymer can be any isocyanate as described above. The polyol used to form the supplemental isocyanate prepolymer is typically selected from the group of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, biopolyols, and combinations thereof. The polyamine used to form the prepolymer is typically selected from the group of ethylenediamine, toluenediamine, diaminodiphenylmethane, and polymethylenepolyphenylenepolyamines, aminoalcohols, and combinations thereof. Examples of suitable amino alcohols include ethanolamine, diethanolamine, triethanolamine, and combinations thereof.

Specific supplemental isocyanates that can be used for the purposes of the present disclosure include, but are not limited to, toluylene diisocyanate; 4,4'-diphenylmethane diisocyanate; mphenylene diisocyanate; 1,5-naphthalene diisocyanate; 4-chloro-1,3-phenylene diisocyanate; tetramethylene diisocyanate; hexamethylene diisocyanate; 1,4-dicyclohexyl diisocyanate; Cyclohexyl 1,4-diisocyanate, Toluylene 2,4,6-triisocyanate, Phenylene 1,3-diisopropyl-2,4-diisocyanate; 1-methyl-3,5-diethyl-2,4-phenylene diisocyanate; 1,3,5-triethyl-2,4-phenylene diisocyanate; 1,3,5-triisopropyl-2,4-phenylene diisocyanate; Bisphenyl 3,3'-diethyl-4,4'-diisocyanate; 3,5,3',5'-tetraethyl-4,4'-diphenylmethane diisocyanate; Diphenylmethane 3,5,3',5'-tetraisopropyl-4,4'-diisocyanate; phenyl 1-ethyl-4-ethoxy-2,5-diisocyanate; benzene 1,3,5-triethyl-2,4,6-triisocyanate; 1-ethyl-3,5-diisopropyl-2,4,6-triisocyanate of benzene and 1,3,5-triisopropyl-2,4,6-triisocyanate of benzene.

The isocyanate component may comprise one or more additives. Additives may be included in the isocyanate component as part of the isocyanate prepolymer or may be added to the isocyanate prepolymer for a specific purpose. Suitable additives for the purposes of the present invention include any additives described herein, as well as other additives known in the art.

Reactive composition with Isocyanate

The polyurethane system of the present invention comprises the isocyanate-reactive resin composition. The isocyanate-reactive composition comprises a second polyether polyol having terminal secondary hydroxyl groups, optionally a third polyether polyol, and an amine-initiated catalytic polyether polyol having primary hydroxyl groups.

Referring now to the second polyol polyether, the second polyol polyether typically has a functionality of greater than about 4, alternatively greater than about 5, alternatively from about 4 to about 8, alternatively from about 5 to about 7, alternatively from about 6; a weight average molecular weight of from about 400 to about 2000, alternatively from about 500 to about 900, alternatively from about 600 to about 800, alternatively from about 650 to about 725 g/mol; a hydroxyl number of from about 30 to about 1100, alternatively from about 300 to about 900, alternatively from about 400 to about 600, alternatively from about 450 to about 550 mg KOH/g; and a viscosity at 25°C of from about 15,000 to about 30,000, alternatively from about 20,000 to about 24,000, alternatively from about 21,000 to about 23,000 cps when tested in accordance with ASTM D2196-15. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description. In some embodiments, the second polyether polyol is started with sorbitol. An initiator, also called a promoter, functions as a reaction base for compounds, such as alkylene oxides, which polymerize to form polyols, and also serves to anchor polyols during formation. The second polyether polyol of these embodiments may comprise EO, PO and/or BO groups and has various percentages of PO coverage. The second polyol polyether has greater than about 90, alternatively greater than about 95, alternatively greater than about 99, alternatively about 100% PO coverage. More specifically, by "about" 100% PO coverage, it is meant that all of the anticipated coverage of the second polyether polyol is PO coverage, with no non-PO coverage resulting from trace amounts of other alkylene oxides or other impurities. As such, the coverage is typically about 100% PO coverage, but can be slightly lower, such as at least about 99% PO coverage, and depends on process variables and the presence of impurities during processing. production of the second polyether polyol.

Coverage of about 100% PO provides substantially (about 100%) all of the secondary hydroxyl groups, which typically react more slowly than the primary hydroxyl groups and produce a more controlled exotherm. In other words, the second polyether polyol having approximately 100% PO end capping also typically reacts more slowly than a polyol having an EO end cap, since a PO capped polyol is sterically hindered and a polyol capped with EO is not sterically hindered.

In one embodiment, the second polyether polyol is a sorbitol-initiated polyether polyol with a PO end cap which has: a functionality of about 6; a weight average molecular weight of about 687 g/mol and a hydroxyl number of about 490 mg KOH/g.

In various embodiments, the second polyether polyol is present in the isocyanate-reactive composition in an amount of from about 20 to about 90, alternatively from about 20 to about 70, alternatively from about 20 to about 60, alternatively from about 30 to about 50 , alternatively from about 35 to about 45% by weight based on the total weight of said isocyanate-reactive composition. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

Referring now to the third polyol polyether, if included, the third polyol polyether is different from said second polyol polyether. The third polyether polyol typically has a functionality of greater than about 2, alternatively about 2 to about 4, alternatively about 3; a weight average molecular weight of from about 300 to about 1500, alternatively from about 400 to about 1300, alternatively from about 500 to about 1100, alternatively from about 600 to about 800, alternatively from about 650 to about 750 g/mol; a hydroxyl number of from about 100 to about 400, alternatively from about 150 to about 300, alternatively from about 200 to about 260 mg KOH/g; and a viscosity at 25°C of from about 200 to about 1000, alternatively from about 200 to about 500, alternatively from about 250 to about 300 cps when tested in accordance with ASTM D2196-15. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

In some embodiments, the third polyether polyol is started with glycerin. An initiator, also called a promoter, functions as a reaction base for compounds, such as alkylene oxides, which polymerize to form polyols, and also serves to anchor polyols during formation. The third polyether polyol of these embodiments may comprise EO, PO and/or BO groups and has various percentages of PO coverage. The third polyether polyol has greater than about 90, alternatively greater than about 95, alternatively greater than about 99, alternatively greater than about 100% PO coverage. More specifically, by "approximately" 100% PO coverage, it is meant that all of the intended coverage of the third polyether polyol is PO coverage, with no non-PO coverage resulting from trace amounts of other alkylene oxides or other impurities. . As such, coverage is typically about 100% PO, but can be slightly lower, such as at least about 99% PO coverage, and depends on process variables and the presence of impurities during product production. third polyether polyol.

Coverage of about 100% PO provides substantially (about 100%) all of the secondary hydroxyl groups, which typically react more slowly than the primary hydroxyl groups and produce a more controlled exotherm. In other words, the third polyether polyol having approximately 100% PO end capping also typically reacts more slowly than a polyol having an EO end cap, since a PO polyol is sterically hindered and a PO capped polyol EO is not sterically hindered.

In one embodiment, the third polyether polyol is a glycerin-initiated polyether polyol with a PO cap which has: a functionality of about 3; a weight average molecular weight of about 700 g/mol, and a hydroxyl number of about 222 to about 237 mg KOH/g.

In various embodiments, the third polyether polyol is present in the isocyanate-reactive composition in an amount of from about 20 to about 70, alternatively from about 20 to about 60, alternatively from about 30 to about 50, alternatively from about 35 to about 45 % by weight based on the total weight of said isocyanate-reactive composition. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

Referring now to the amine initiated catalytic polyol polyether, the amine initiated catalytic polyol polyether typically has a functionality of greater than about 3, alternatively about 2 to about 6, alternatively about 3 to about 5, alternatively about 4; a weight average molecular weight of from about 200 to about 1500, alternatively from about 200 to about 1000, alternatively from about 200 to about 500, alternatively from about 250 to about 450, alternatively from about 300 to about 400 g/mol; a hydroxyl number of from about 100 to about 1000, alternatively from about 300 to about 700, alternatively from about 400 to about 500, alternatively from about 450 to about 550mg KOH/g; and a viscosity at 25°C of from about 200 to about 1000, alternatively from about 200 to about 500, alternatively from about 250 to about 350 cps when tested in accordance with ASTM D2196-15. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

In some embodiments, the amine initiated catalytic polyol polyether is initiated with monoethanolamine. An initiator, also called a promoter, functions as a reaction base for compounds, such as alkylene oxides, which polymerize to form polyols, and also serves to anchor polyols during formation. As discussed above, the catalytic polyol is derived from an amine-based starter. The catalytic polyol is referred to as a "catalytic" polyol because the catalytic polyol can be used in place of a catalyst to facilitate the chemical reaction of the isocyanate with the polyol component. Stated another way, a polyol component that includes the catalytic polyol will typically chemically react with the isocyanate at lower temperatures in the presence of less catalyst (even without catalyst) than a polyol component that does not include the catalytic polyol. Without being bound or limited by any particular theory, it is believed that the amine content of the catalytic polyol facilitates the reaction of the isocyanate with the polyol component.

The amine initiated catalytic polyol polyether of these embodiments may comprise EO, PO and/or BO groups and have various percentages of EO coverage. The amine initiated catalytic polyol polyether has greater than about 90, alternatively greater than about 95, alternatively greater than about 99, alternatively greater than about 100% EO coverage. More specifically, by "approximately" 100% EO coverage, it is meant that all of the intended coverage of the amine-initiated catalytic polyether polyol is EO coverage, with no non-EO coverage resulting from trace amounts of other alkylene oxides. or other impurities. As such, the coverage is typically about 100% EO coverage, but can be slightly lower, such as at least about 99% EO coverage, and depends on process variables and the presence of impurities during the process. production of the amine-initiated catalytic polyol polyether.

The terminal capping of about 100% EO provides substantially (about 100%) all of the primary hydroxyl groups, which normally react faster than the secondary hydroxyl groups and produce an enhancement of the catalytic effect. In other words, the catalytic amine initiated polyether polyol having approximately 100% EO end capping typically reacts faster than the second and third polyether polyols having PO end capping, since an OP protected polyol is sterically hindered.

In one embodiment, the amine initiated catalytic polyether polyol is an EO capped polyether polyol having: a functionality of about 4; a weight average molecular weight of about 334 g/mol, and a hydroxyl number of about 500 mg KOH/g.

In various embodiments, the amine-initiated catalytic polyol polyether is present in the isocyanate-reactive composition in an amount of less than about 10, less than about 8, about 1 to about 10, alternatively about 2 to about 8, alternatively from about 3 to about 7, alternatively from about 4 to about 6% by weight based on the total weight of said isocyanate-reactive composition. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

The isocyanate-reactive resin composition may optionally include one or more than one supplemental polyol that is different from the second polyether polyol, the third polyether polyol, and the amine-initiated catalytic polyol. The supplemental polyol includes one or more OH functional groups, typically at least two OH functional groups. Typically, the supplemental polyol is selected from the group of polyether polyols, polyester polyols, polyether/ester polyols, and combinations thereof; however, other polyols can also be used. The supplemental polyol can be included in the isocyanate-reactive resin composition in various amounts.

The isocyanate-reactive resin composition typically includes a catalyst. The isocyanate-reactive resin composition may include one or more suitable catalysts selected from those known in the art. The catalyst is typically present in the isocyanate-reactive resin composition to catalyze the exothermic reaction between the isocyanate-reactive resin composition and the isocyanate. It should be appreciated that the catalyst is typically not consumed in the exothermic reaction between the isocyanate-reactive resin composition and the isocyanate. That is, the catalyst typically participates in the exothermic reaction, but is not consumed by it. Examples of suitable catalysts include, but are not limited to, gelation catalysts, eg, amine catalysts in dipropylene glycol; foaming catalysts, for example, bis(dimethylaminoethyl) ether in dipropylene glycol; and metal catalysts, eg, tin, bismuth, lead, etc. In some embodiments, the isocyanate-reactive resin composition comprises one or more amine catalysts, eg, N,N-dimethylcyclohexylamine (DMCHA). If included, the catalyst may be included in various amounts.

The isocyanate-reactive resin composition typically includes a foam stabilizer. The isocyanate-reactive resin composition may include one or more suitable foam stabilizers selected from those known in the art. Non-limiting examples of suitable foam stabilizers include copolymers of siloxaneoxyalkylene and other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oils, castor oil esters, ricinoleic acid esters, sulfated red castor oil, and peanut oil. In one embodiment, the foam stabilizer is a hydrolysis resistant polyethersiloxane copolymer. If included, the foam stabilizer may be included in the isocyanate-reactive resin composition in various amounts.

The isocyanate-reactive resin composition may optionally include a surfactant. The isocyanate-reactive resin composition may include one or more suitable surfactants selected from those known in the art. The surfactant typically supports homogenization of the foaming agent and polyol and regulates the cell structure of the polyurethane foam. Non-limiting examples of suitable surfactants include various silicone surfactants, sulfonic acid salts, for example, alkali metal and/or ammonium salts of oleic acid, stearic acid, dodecylbenzene or dinaphthylmethane disulfonic acid, and ricinoleic acid, foam stabilizers such as such as siloxaneoxyalkylene copolymers and other organopolysiloxanes, oxyethylated alkyl phenols, oxyethylated fatty alcohols, paraffin oils, castor oil, castor oil esters and ricinoleic acid esters, and cell regulators, such as paraffins, fatty alcohols and dimethyl polysiloxanes. If included, the surfactant may be included in the isocyanate-reactive resin composition in various amounts.

The isocyanate-reactive resin composition may optionally include a UV package (eg, a UV component comprising one or more UV components such as UV components selected from ultraviolet absorbers, hindered amine light stabilizers, optical brighteners, and combinations thereof). .

In many embodiments, the UV package comprises one or more than one amine, ie, a single type of amine or more than one type of amine. The amine can include one or more amine groups. That is, the amine can be mono, di, tri, amine, etc. The amine can include a tertiary amine group, a secondary amine group, a primary amine group, or combinations thereof. The amine can include any combination of tertiary, primary, and secondary amines. For example, the amine can include 2 tertiary amine groups. In many embodiments, the amine comprises 1 or more -COOC- groups, 1 or more piperdinyl groups, and/or 1 or more sebacate groups. In various embodiments, the amine is hydroxy functional, that is, it includes 1 or more hydroxyl groups. One or more amines in the UV package are different from the amine-initiated polyols and additives described above.

In various embodiments, the amine has a weight average molecular weight (Mw) of from about 100 to about 2000, alternatively from about 100 to about 1500, alternatively from about 100 to about 1000, alternatively from about 100 to about 900, alternatively from about 100 to about 700, alternatively from about 100 to about 600, alternatively from about 100 to about 500, alternatively from about 100 to about 400, alternatively from about 200 to about 300 g/mol.

In a particular embodiment, the UV package includes (1) at least 1 piperdinyl-functional multiple diamine and at least a few first amines, some of which

For example, in one such embodiment, the UV package includes:

(1) a first hindered amine light stabilizer liquid component comprising a mixture of bis(1,2,2,6,6,-pentamethyl-4-piperdinyl) sebacate and 1-(methyl)-8-sebacate (1,2,2,6,6-pentamethyl-4-piperdinyl) typically dispersed in water;

(2) a second liquid hindered amine light stabilizer (hydroxyphenyl-triazine (HPT) UV absorber) comprising a mixture of 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl ]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-[(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis( 2,4-dimethylphenyl)-1,3,5-triazine dispersed in 1-methoxy-2-propanol; and

(3) an optical brightener comprising a mixture of N-(4-ethoxycarbonylphenyl)-N-phenyl formamidine and having an OH content of from about 13 to about 15 mg/KOH/g and a viscosity at 25°C of about 700 to approximately 1500 cps when tested in accordance with ASTM D2196-15. In various embodiments, one or more UV package amines are present in the isocyanate-reactive composition in an amount of less than about 10, less than about 8, about 0.1 to about 6, alternatively about 0.2 to about 8, alternatively from about 0.3 to about 7, alternatively from about 0.4 to about 6% by weight based on the total weight of said isocyanate-reactive composition. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description. For example, one or more amines may be present in the isocyanate-reactive composition in amounts of any of the following lower range values: 0.1, 0.2, 0.3, 0.4, 0.5, 0, 6, 0.7, 0.8, 0.9, 1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2, 1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3, 4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5 to any of the following higher range values: 1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1 .9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2 , 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4 .6, 4.7, 4.8, 4.9, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9 , 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.7, 6.9, 7, 7.1, 7 0.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9 or 8% by weight based on the total weight of said isocyanate-reactive composition. Of course, it should be appreciated that more than one amine may be included in the lubricant composition, in which case the total amount of all included amines is within the above ranges.

The isocyanate-reactive resin composition may optionally include one or more additives. The additive may include any suitable additive or mixtures of additives known in the art. Additives suitable for the purposes of the present invention include, but are not limited to, chain extenders, crosslinkers, chain terminators, processing additives, adhesion promoters, antioxidants, defoamers, antifoaming agents, water scavengers, molecular sieves. , flame retardants, fumed silicas, fillers, thixotropic agents, silicones, colorants, inert diluents and combinations thereof. If included, the additive may be included in the isocyanate-reactive resin composition in various amounts.

The isocyanate component and the isocyanate-reactive composition react in the presence of a foaming agent to form the polyurethane foam article. As is known in the art, during the exothermic reaction of the isocyanate-reactive resin composition and the isocyanate, the foaming agent promotes the release of an expanding gas which forms spaces, or cells, in the polyurethane foam article. The foaming agent may be a physical foaming agent, a chemical foaming agent, or a combination of a physical foaming agent and a chemical foaming agent. The foaming agent may be included in the isocyanate-reactive composition.

The term physical foaming agent describes foaming agents that do not chemically react with the isocyanate and/or the isocyanate-reactive component. The physical foaming agent can be a gas or a liquid. The liquid physical foaming agent typically evaporates to a gas when heated, and typically returns to a liquid when cooled. Non-limiting examples of physical blowing agents include hydrofluorocarbons (HFCs), hydrocarbons, and combinations thereof.

The term chemical foaming agent describes foaming agents that react chemically with isocyanate or other components to release a gas for foaming. Two specific and non-limiting examples of chemical foaming agents are water and formic acid. In various embodiments, the foaming agent includes formic acid, water, and combinations thereof.

As stated above, the polyurethane foam article comprises the reaction product of the isocyanate component and the isocyanate-reactive composition. Typically, the isocyanate-reactive resin composition and the isocyanate are combined with an isocyanate index of from about 75 to about 140, alternatively from about 90 to about 140, alternatively from about 90 to about 130, alternatively from about 90 to about 130, alternatively from about 100 to about 130, alternatively from about 110 to about 130, alternatively from about 115 to about 125.

In many embodiments, the polyurethane foam article is a surfboard core, ie, it is used to form a surfboard. The polyurethane system of the present invention produces a polyurethane foam article having excellent strength, color, and color stability. Without being bound by theory, it is believed that the specific polyol reacted to produce the isocyanate prepolymer and the formation of the prepolymer reduces the exotherm produced when the isocyanate component and the isocyanate-reactive component react to form the core of the surfboard. In addition, the particular combination of slow and "slow" secondary terminated polyols with a "catalytic" polyol included in the isocyanate-reactive composition react to produce surfboard cores that have excellent strength, uniform cell structure and a white appearance. with excellent UV stability. That is, the exotherm is controlled by first producing an isocyanate prepolymer and then further controlled by reacting the isocyanate with a particular combination of "slow" polyols and "catalytic" polyols to provide unexpectedly excellent results.

In addition, the polyurethane system forms a surfboard core which molds and polishes well. Furthermore, surfboards formed from the surfboard cores of the present invention have better performance than surfboards formed from conventional foam cores comprising toluene diisocyanate-based foams or styrenic foams.

In one embodiment, a composite article including the polyurethane foam article as the surfboard core/part and a laminate composition comprising epoxy resin and fiberglass disposed on the polyurethane foam article is also described herein. . In another embodiment, the surfboard core is coated with a laminate composition comprising polyester resin (as opposed to the laminate composition comprising epoxy resin and fiberglass) to form the laminate. In various embodiments, due to Since the surfboard core/polyurethane foam article has uniform cell structure and excellent strength, only a single coating or layer of the laminate composition is required.

A Method for Manufacturing the Polyurethane Foam Article

The subject matter of the invention also provides a method of manufacturing the polyurethane foam article comprising the steps of reacting the first polyether polyol and diphenylmethane diisocyanate to form the isocyanate prepolymer, and reacting the isocyanate prepolymer with the reactive composition. with isocyanate in the presence of the foaming agent to form the polyurethane foam article. The isocyanate component, isocyanate prepolymer and isocyanate-reactive composition are exactly as described above.

The unreacted isocyanate-reactive resin composition, the isocyanate component, and the foaming agent are collectively referred to as the polyurethane system. The method includes the steps of providing the isocyanate-reactive resin composition, the isocyanate component and the foaming agent. In other words, the isocyanate-reactive resin composition, the isocyanate component and the foaming agent may be supplied for use in the method. The foaming agent may be provided with the isocyanate-reactive resin composition or may be provided separately. Typically, the isocyanate-reactive resin composition and isocyanate component are formulated off-site and delivered to an area where they are used. Typically, the polyurethane system, including the isocyanate-reactive resin composition and the isocyanate, are supplied together.

The isocyanate-reactive resin composition and the isocyanate may be combined (reacted) by any mechanism known in the art to form the reaction mixture. Typically, the blending step occurs in a mixing apparatus, such as a static mixer, impact mixing chamber, or mixing pump. The isocyanate-reactive resin composition and the isocyanate can also be combined in a spray nozzle.

In a typical embodiment, the step of reacting the isocyanate prepolymer with the isocyanate-reactive composition is further defined as casting a reaction mixture comprising the isocyanate prepolymer and the isocyanate-reactive composition. For example, the reaction mixture can be molded into the shape of a surfboard, ie, into a surfboard core. In such embodiments, the molding step may be performed at a pressure of from about 100 to about 2,000 psi, alternatively from about 200 to about 2,000, alternatively from about 1,000 to about 2,000 psi, alternatively from about 1,250 to about 1,750 psi and/or temperatures. from about 25 to about 95 °C. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description. For example, the molding step can be performed at pressures of any of the following lower range values: 50, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300 , 1400, or 1500 to any of the following larger range values: 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, or 2000psi. For example, the molding step can be performed at temperatures of any of the following lower range values: 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 to any of the following upper range values: 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95, °C.

In some embodiments of the method, the polyurethane foam article is cured (in-mold or out-of-mold) at temperatures any of the following lower range values 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 to any of the following higher range values 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95, °C, for times of any of the following lower range values 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 60, to any of the following higher range values: 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 minutes.

In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

In some embodiments of the method, the isocyanate-reactive resin composition and the isocyanate are heated to a temperature of from about 30°C to about 55°C prior to the reaction/molding step. In the method, the isocyanate-reactive resin composition and the isocyanate component or isocyanate prepolymer are reacted with an isocyanate number as stated above, for example, with an isocyanate number of from about 90 to about 120.

The method may include the step of applying a laminate composition to the outer surface of a polyurethane foam article (eg, a surfboard core) to form the laminate. In some embodiments, the method laminate composition comprises polyester resin. In other embodiments, the method laminate composition comprises epoxy resin and fiberglass. Additionally, the method may include the step of heating the polyurethane foam article having the composition laminated thereon to cure the laminated composition and form a laminate. For example, the polyurethane foam article that it has the laminate composition disposed thereon at a temperature of 35 to 85°C for up to 8 hours. In various non-limiting embodiments, all values and ranges of values between the values mentioned above are expressly contemplated in the present description.

The following examples are intended to illustrate the present invention and should not be construed as limiting the scope of the present invention in any way.

Example

Example 1 is described in the present description. The isocyanate component of Example 1 consists essentially of the isocyanate prepolymer. The isocyanate prepolymer is described in Table 1, with amounts in % by weight based on the total weight of the components used to form the isocyanate prepolymer or based on the total weight of the isocyanate prepolymer. The components of Table 1 are combined or reacted to form the isocyanate prepolymer.

Table 1: Isocyanate Prepolymer Formation

Isocyanate is diphenylmethane diisocyanate comprising traces (eg, less than 0.5% by weight) of the 2,2'-isomer, about 50% by weight of the 2,4'-isomer and about 50% by weight of the 4,4'-isomer. The first polyether polyol is a pentaerythritol initiated polyether polyol with a PO cap which has: a functionality of about 4; a weight average molecular weight of about 400 g/mol and a hydroxyl number of about 555 mg KOH/g.

The isocyanate system of Example 1 is described in Table 2, with amounts in % by weight based on the total weight of the isocyanate-reactive composition. The components of Table 2 react under pressure in a mold to form the polyurethane foam article having the shape of a surfboard core.

Table 2: The Polyurethane Foam Article

The second polyether polyol is a PO capped sorbitol initiated polyether polyol which has: a functionality of about 6; a weight average molecular weight of about 687 g/mol and a hydroxyl number of about 490 mg KOH/g.

The third polyether polyol is a PO capped glycerin initiated polyether polyol which has: a functionality of about 3; a weight average molecular weight of about 700 g/mol, and a hydroxyl number of about 222 to about 237 mg KOH/g.

The amine initiated catalytic polyol is an EO capped polyether polyol which has: a functionality of about 4; a weight average molecular weight of about 334 g/mol, and a hydroxyl number of about 500 mg KOH/g.

Foam Stabilizer is a hydrolysis resistant polyethersiloxane copolymer.

Catalysts A and B are amine catalysts.

The UV package comprises bis(1,2,2,6,6,-pentamethyl-4-piperdinyl) sebacate and 1-(methyl)-8-(1,2,2,6,6-pentamethyl-4-sebacate). -piperdinyl), 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2- [4-[(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and N-(4-ethoxycarbonylphenyl)- N-phenyl formamidine.

Foaming Agent A is water.

Foaming Agent B is formic acid.

Advantageously, the polyurethane foam article of the present invention improves on the prior art. That is, the polyurethane system of Example 1 produces a polyurethane foam article which has excellent strength, color and color stability when used as/in a surfboard core. The particular combination of slow and "slow" secondary polyols terminated with a "catalytic" polyol included in the isocyanate-reactive composition reacts to produce surfboard cores that have excellent strength, uniform cell structure, and a white appearance with excellent UV stability. That is, the exotherm of the polyurethane is controlled by first producing an isocyanate prepolymer, and then further controlled by reacting the isocyanate with a particular combination of "slow" polyols and "catalytic" polyols to provide unexpectedly excellent results.

In addition, the polyurethane system of Example 1 forms a surfboard core that molds and polishes well. Furthermore, surfboards formed from the surfboard cores of the present invention have better performance than surfboards formed from conventional foam cores comprising toluene diisocyanate-based foams or styrenic foams.

It is also to be understood that any ranges and subranges relied upon to describe various embodiments of the present invention, independently and collectively, are within the scope of the appended claims, and all ranges, including values, are understood to be described and contemplated. total and/or fractional, even if such values are not expressly written in this description. One skilled in the art will readily recognize that the listed ranges and subranges sufficiently describe and allow for various embodiments of the present invention, and such ranges and subranges may be further delimited as halves, thirds, fourths, fifths, etc. As just one example, a range "0.1 to 0.9" can be further delineated into a lower third, i.e. 0.1 to 0.3, a middle third, i.e. 0.4 to 0 .6, and an upper third, i.e. 0.7 to 0.9, which individually and collectively are within the scope of the appended claims, and may be individually and/or collectively relied upon and provide adequate support for specific embodiments within the scope of the appended claims. Furthermore, with respect to language which defines or modifies an interval, such as "at least", "greater than", "less than", "not greater than" and the like, such language should be understood to include subintervals and/or a upper or lower limit. As another example, a range of "at least 10" inherently includes a subrange of at least 10 to 35, a subrange of at least 10 to 25, a subrange of 25 to 35, and so on, and each subrange can be individually trusted. and/or collectively and provides suitable support for specific embodiments within the scope of the appended claims. Finally, an individual number within a described range can be relied upon and provide suitable support for specific embodiments within the scope of the appended claims. For example, a range "1 to 9" includes several individual whole numbers, such as 3, as well as individual numbers that include a decimal point (or fraction), such as 4.1, both of which are reliable and provide adequate support for certain embodiments within the scope of the appended claims.

The present invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be of a descriptive rather than limiting nature.

Claims (17)

1. A polyurethane foam article comprising the reaction product of: (A) an isocyanate component comprising an isocyanate prepolymer, said isocyanate prepolymer comprising the reaction product of: (i) a first polyether polyol; and (ii) a diphenylmethane diisocyanate, said diphenylmethane diisocyanate comprising: from 40% by weight to 60% by weight of 2,4'-isomer based on the total weight of diphenylmethane diisocyanate; from 40% by weight to 60% by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and less than 10% by weight of 2,2'-isomer based on the total weight of diphenylmethane diisocyanate; and (B) an isocyanate-reactive composition comprising: (i) a second polyether polyol having terminal secondary hydroxyl groups; and (ii) an amine initiated catalytic polyol polyether having primary hydroxyl groups; in the presence of a foaming agent. 2. A polyurethane foam article as set forth in claim 1, wherein said first polyether polyol has a weight average molecular weight of 200 to 900 g/mol. 3. A polyurethane foam article as set forth in claim 1 or 2, wherein said first polyether polyol has a hydroxyl functionality of from 2 to 5. 4. A polyurethane foam article as set forth in any preceding claim, wherein said first polyol polyether comprises greater than 99% propyleneoxy endcaps based on the total number of endcaps present in said first polyol polyether. 5. A polyurethane foam article as set forth in any preceding claim, wherein said first polyether polyol is present in said isocyanate prepolymer in an amount of from 2 to 20% by weight based on the total weight of said isocyanate prepolymer. , and said diphenylmethane diisocyanate is present in said isocyanate prepolymer in an amount of 80 to 98% by weight based on the total weight of said isocyanate prepolymer. 6. A polyurethane foam article as set forth in any preceding claim, wherein said isocyanate prepolymer has an NCO content of from 15 to 40% by weight based on the total weight of said isocyanate prepolymer. 7. A polyurethane foam article as set forth in any preceding claim, wherein said second polyether polyol has a weight average molecular weight of 400 to 2000 g/mol and/or a hydroxyl functionality of 4 to 8. A polyurethane foam article as set forth in any preceding claim, wherein said second polyether polyol is present in said isocyanate-reactive composition in an amount of from 20 to 90% by weight based on the total weight of said reactive composition. with isocyanate. A polyurethane foam article as set forth in any preceding claim, wherein said isocyanate-reactive composition further comprises a third polyol polyether having terminal secondary hydroxyl groups which is different from said second polyol polyether. A polyurethane foam article as set forth in claim 9, wherein said third polyether polyol has a weight average molecular weight of 300 to 1500 g/mol and/or a hydroxyl functionality of 2 to 4. A polyurethane foam article as set forth in claim 9 or 10, wherein said third polyol polyether is present in said isocyanate-reactive composition in an amount of from 20 to 60% by weight based on the total weight of said reactive composition with isocyanate. A polyurethane foam article as set forth in any preceding claim, wherein said amine initiated catalytic polyol polyether has a weight average molecular weight of from 200 to 1500 g/mol and/or a hydroxyl functionality of from 2 to 6 . A polyurethane foam article as set forth in any preceding claim, wherein said amine initiated catalytic polyol polyether is present in said isocyanate-reactive composition in an amount of less than 10% by weight based on the total weight of said reactive composition with isocyanate. 14. A composite article comprising: a core comprising said polyurethane foam article as set forth in any preceding claim; and a laminate comprising fiberglass and epoxy disposed on said polyurethane foam article. 15. A surfboard comprising said composite article as set forth in any preceding claim. 16. A method of manufacturing a polyurethane foam article comprising the steps of: (A) reacting a first polyether polyol and diphenylmethane diisocyanate to form an isocyanate prepolymer, wherein the diphenylmethane diisocyanate comprises: 40% by weight % by weight of 2,4'-isomer based on the total weight of diphenylmethane diisocyanate; 40% by weight % by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and less than 10% by weight of 2,2'-isomer based on the total weight of diphenylmethane diisocyanate; and (B) reacting the isocyanate prepolymer with an isocyanate-reactive composition in the presence of a foaming agent to form the polyurethane foam article, the isocyanate-reactive resin composition comprising: (i) a second polyether polyol having terminal secondary hydroxyl groups; and (ii) an amine initiated catalytic polyol polyether having primary hydroxyl groups. 17. A polyurethane system for use in forming a polyurethane foam article for a surfboard, said polyurethane system comprising: (A) an isocyanate component comprising an isocyanate prepolymer, said isocyanate prepolymer comprising the reaction product of: (i) a first polyether polyol; and (ii) a diphenylmethane diisocyanate, said diphenylmethane comprising: from 40% by weight to 60% by weight of 2,4'-isomer based on the total weight of diphenylmethane diisocyanate; from 40% by weight to 60% by weight of 4,4'-isomer based on the total weight of diphenylmethane diisocyanate; and less than 10% by weight of 2,2'-isomer based on the total weight of diphenylmethane diisocyanate; and (B) an isocyanate-reactive composition comprising: (i) a second polyether polyol having terminal secondary hydroxyl groups and a hydroxyl functionality of from 5 to 7; (ii) a third polyether polyol having terminal secondary hydroxyl groups and a hydroxyl functionality of from 2 to 4; and (iii) an amine initiated catalytic polyol polyether having primary hydroxyl groups and is present in said isocyanate-reactive composition in an amount of less than 10% by weight based on the total weight of said isocyanate-reactive composition.